| 摘要 |
PURPOSE:To correct without a multiplier the variation of light quantity and the sensitivity of a sensor by providing a memory storing a value corrected the shading distortion in an address that is determined by a reference read-signal read the reference plane and an original read-signal read an original. CONSTITUTION:Prior to starting the reading of the original, the signal to be the reference in the correcting is generated, which is converted to a digital signal by an A/D converter 3, and is stored in a RAM 5. Then, when the original is transferred to the reading plane, a read information obtained from the original is outputted from a sensor array 1, which is A/D-converted like the signal as to the reference plane, and is temporarily stored in a register 6. The data read out from the register 6 is corrected of its shading part by a ROM 8 based on the reference data stored in the RAM 5. The data is thereafter corrected of its density part by a ROM 9 based on the darkness level, and accordingly, an output corrected in shading and density V0 is obtained.
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